Otocheck ABR
User Manual
45
ABR test procedure
If the position of the
Fit Size Indicator
corresponds with the age of the
patient and
Checkfit
is displayed on the top of the screen then the probe
fit and the test conditions are adequate for testing. The
Stimulus and Noise
OK indicators
(above the screen) should also be illuminated. Select
Start
to continue the test.
If there is a disagreement between the
Fit Size Indicator
and the ear
canal size expected of your patient, then there may be a problem with the
probe or the probe fit. For example: an indication of a large ear canal in a
neonate may occur if the probe has fallen out of the ear or if the probe is
blocked; an indication of a small ear canal in an adult may occur because
of wax blocking the canal.
Noise level indicator
A Noise Level Indicator is shown on the right of the
Checkfit
screen. The
red/green bar moves in response to changes in noise. For good testing
conditions the bar should be green and remain consistently below the
Noise Reject Level, which is represented by the horizontal line across the
Noise Level Indicator. In poor testing conditions, when the noise level is
above the Noise Reject Level, the bar will be red.
Ear cups
The test stimulus in ABR tests can be provided either by inserting the
probe into the ear, as for OAE testing, or by applying an ear cup to the
ear and inserting the probe into the ear cup. Ear cups can be particularly
useful in neonates with very small ear canals where a secure probe fit is
not possible. They can also be useful in preventing the probe from being
dislodged by movement during testing.